215
FXUS65 KBYZ 262321
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
521 PM MDT SAT SEP 26 2026
KEY MESSAGES
- UNSETTLED CONDITIONS SUNDAY INTO MONDAY WILL KEEP SEASONABLE
TEMPERATURES AROUND AND INTRODUCE SMALL TO MODERATE CHANCES FOR
PRECIPITATION.
- A FEW STRONG STORMS ARE POSSIBLE SUNDAY EVENING INTO THE
OVERNIGHT HOURS ACROSS SOUTHEAST MT. MAIN THREATS WILL BE HEAVY
RAIN, SMALL HAIL AND GUSTY WINDS.
UPDATE
UPDATED PRECIPITATION CHANCES AND ASSOCIATED GRIDS FOR TONIGHT
INTO TOMORROW. SW-NE ORIENTED JET STREAK WILL BE OVER THE AREA
TONIGHT INTO TOMORROW MORNING. THIS ENERGY OVER THE WESTERN
MOUNTAINS WILL KEEP WINDS ELEVATED OVER THE HIGHER TERRAIN TONIGHT
ALONG WITH BRINGING SCATTERED LIGHT SHOWER ACTIVITY AT TIMES.
LOWER ELEVATIONS WEST LOOK TOO DRY TO SUPPORT MEASURABLE
PRECIPITATION AT THIS TIME. THE RIGHT REAR QUADRANT (LIFT) WILL
CROSS THE SOUTHERN AND EASTERN ZONES OVERNIGHT INTO TOMORROW
MORNING, BRINGING ENOUGH UPWARD MOTION FOR AT LEAST A CHANCE OF
SHOWERS AND MAYBE AN EARLY MORNING THUNDERSTORM OR TWO TO THIS
AREA. THIS ENERGY WILL BE AIDED BY AN OVERNIGHT NORTHERLY WIND
PUSH WHICH WILL VEER TO THE SOUTHEAST EARLY IN THE MORNING OVER SE
MONTANA BRINGING INCREASES LOW LEVEL MOISTURE AND LOW LEVEL
CONVERGENCE. A FEW MODELS ARE ADVERTISING A QUICK TENTH OF AN INCH
WITH A FEW STRONGER SHOWERS, BUT OVERALL THIS ACTIVITY DOESN'T
LOOK WIDESPREAD OR OF MUCH CONSEQUENCE, JUST AN INCREASE OVER WHAT
HAD BEEN ADVERTISED. REST OF THE FORECAST IS ON TRACK. CHAMBERS
DISCUSSION
TODAY THROUGH FRIDAY...
FOLLOWING THE SHORTWAVE AND ASSOCIATED COLD FRONT THAT MOVED
THROUGH THIS MORNING, INCREASING SOUTHWEST FLOW IS EXPECTED INTO
SUNDAY. ALTHOUGH MODELS KEEP WITH THE TREND OF SPLITTING THE
STRONGEST ENERGY TO THE NORTH AND SOUTH, WEAK ENERGY IN THE LOW
LEVELS LOOK TO PROVIDE ENOUGH FORCING TO POTENTIALLY PRODUCE A FEW
STRONGER THUNDERSTORMS SUNDAY EVENING INTO THE OVERNIGHT HOURS.
ONE CAVEAT TO THE POTENTIAL FOR THUNDERSTORMS SUNDAY EVENING IS
MODEL SOUNDINGS SEEMING PRETTY CONSISTENT WITH A CAP OR INVERSION,
PREVENTING THUNDERSTORM DEVELOPMENT. THAT BEING SAID, IF THE
INSTABILITY PRESENT (500-1000 J/KG MUCAPE) IS ABLE TO BE TAPPED
INTO, THE BULK SHEAR PRESENT (35-45KTS) WOULD SUPPORT A FEW STRONG
STORMS CAPABLE OF PRODUCING HEAVY RAIN, SMALL HAIL AND GUSTY
WINDS. CURRENTLY, THERE IS ABOUT A 30-50% CHANCE FOR AT LEAST A
QUARTER INCH OF PRECIPITATION FOR THE HIGHER TERRAIN AND THE
MT/DAKOTAS BORDER. ANY STRONGER THUNDERSTORM WILL BE CAPABLE OF
PRODUCING LOCALLY HIGHER AMOUNTS WITH ATMOSPHERIC MOISTURE AT
150-200% OF NORMAL. AS TRAILING ENERGY FROM THIS SYSTEM MOVES
OVER THE REGION, SMALL CHANCES FOR SHOWERS WILL REMAIN IN THE
FORECAST FOR MONDAY. AS A MORE WESTERLY FLOW ALOFT MOVES IN
TUESDAY, CONDITIONS LOOK TO BECOME DRY WITH SEASONABLE
TEMPERATURES IN PLACE. TOWARDS THE END OF THE WEEK THERE IS A LOT
OF SPREAD, BUT ENSEMBLES ARE HINTING AT A COOLER TROUGH MOVING
THROUGH. WILL BE SOMETHING TO WATCH THROUGH THE WEEK. TS
AVIATION
00Z TAF/AVIATION DISCUSSION...VFR CONDITIONS WILL PREVAIL
THROUGH THE DAY SUNDAY. A SURFACE WIND SHIFT TO THE NORTH WILL
MOVE INTO THE FORECAST AREA THIS EVENING, WITH WINDS QUICKLY
SHIFTING NORTHEAST OVERNIGHT, AND TO THE EAST BY TOMORROW MORNING.
WINDS SPEEDS WILL BE GENERALLY UNDER 15KTS WITH THIS SHIFT, BUT
HIGHER EXPOSED LOCATIONS COULD SEE SOME GUSTS IN THE 20S. A SW-NE
ORIENTED JET STREAM SITTING OVER THE FORECAST AREA WILL PROVIDE
ENOUGH ENERGY FOR A FEW LIGHT SHOWERS FROM THE SOUTHWEST MOUNTAINS
NORTHEAST INTO SE MONTANA AFTER 06Z THROUGH TOMORROW MORNING WITH
GUSTS TO 25KTS POSSIBLE NEAR PRECIPITATION AREAS. HOWEVER THIS
ACTIVITY SHOULD NOT IMPACT FLIGHT CATEGORIES. SOUTHEAST WINDS
INCREASE TO 20 TO 30KTS OVER SE MONTANA LATE SUNDAY AFTERNOON. A
STRONGER FRONT MOVING INTO THE AREA SUNDAY EVENING FROM THE WEST
WILL INCREASE SHOWER/ISOLATED THUNDERSTORM COVERAGE LATE AFTERNOON
INTO TOMORROW EVENING, WITH BETTER CHANCES FOR MVFR TO LOCAL IFR
CONDITIONS AS THE EVENING PROGRESSES. CHAMBERS
PRELIMINARY POINT TEMP/POPS
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 069 046/064 047/068 046/074 050/075 048/070 048/070
0/B 11/E 21/E 00/U 00/U 00/U 00/B
LVM 069 038/063 039/068 038/074 044/074 041/072 042/072
0/B 11/E 22/W 00/U 00/U 00/U 01/B
HDN 071 043/068 045/068 043/075 046/076 045/072 045/072
0/U 11/E 21/E 10/U 00/U 00/U 00/B
MLS 070 044/068 051/069 047/073 049/074 048/069 048/070
0/U 11/E 31/E 00/U 00/U 00/U 00/B
4BQ 070 046/070 053/068 048/073 050/075 049/070 048/072
0/U 11/E 42/W 10/U 00/U 00/U 00/U
BHK 070 043/069 049/069 046/073 047/075 045/068 044/070
0/U 22/W 83/W 10/U 00/U 00/U 01/B
SHR 072 041/068 046/065 041/071 042/074 043/071 043/072
0/U 11/E 25/W 30/U 00/U 10/U 01/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
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